Re: [PATCH v14 0/2] drm: add kms driver for loongson display controller

[Sui Jingfeng]

Hi,


Any ideas for this trivial DC driver? Sorry about my broken English.

What to do next? Send a new version?

Please Help!


On 2023/5/20 18:57, Sui Jingfeng wrote:
> From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx>
>
> Loongson display controller IP has been integrated in both Loongson north
> bridge chipset(ls7a1000/ls7a2000) and Loongson SoCs(ls2k1000/ls2k2000), it
> has been even included in Loongson self-made BMC products.
>
> This display controller is a PCI device. It has two display pipes and each
> display pipe support a primary plane and a cursor plane. For the DC in the
> ls7a1000 and ls2k1000, each display pipe has a DVO output interface which
> provide RGB888 signals, vertical & horizontal synchronisations and pixel
> clock. Each CRTC is able to support 1920x1080@60Hz, the maximum resolution
> of each display pipe is 2048x2048 according to the hardware spec.
>
> For the DC in LS7A2000, each display pipe is equipped with a built-in HDMI
> encoder which is compliant with the HDMI 1.4 specification, thus it support
> 3840x2160@30Hz. The first display pipe is also equipped with a transparent
> vga encoder which is parallel with the HDMI encoder. The DC in LS7A2000 is
> more complete compare with the one in old chips, besides above feature, it
> has two hardware cursors, two hardware vblank counter and two scanout
> position recorders unit. It also support tiled framebuffer format which
> can be scanout the tiled framebuffer rendered by the LoongGPU directly.
>
> v1 -> v2:
>   1) Use hpd status reg when polling for ls7a2000
>   2) Fix all warnings emerged when compile with W=1
>
> v2 -> v3:
>   1) Add COMPILE_TEST in Kconfig and make the driver off by default
>   2) Alphabetical sorting headers (Thomas)
>   3) Untangle register access functions as much as possible (Thomas)
>   4) Switch to TTM based memory manager and prefer cached mapping
>      for Loongson SoC (Thomas)
>   5) Add chip id detection method, now all models are distinguishable.
>   6) Revise builtin HDMI phy driver, nearly all main stream mode
>      below 4K@30Hz is tested, this driver supported these mode very
>      well including clone display mode and extend display mode.
>
> v3 -> v4:
>   1) Quickly fix a small mistake.
>
> v4 -> v5:
>   1) Drop potential support for Loongson 2K series SoC temporary,
>      this part should be resend with the DT binding patch in the future.
>   2) Add per display pipe debugfs support to the builtin HDMI encoder.
>   3) Rewrite atomic_update() for hardware cursors plane(Thomas)
>   4) Rewrite encoder and connector initialization part, untangle it
>      according to the chip(Thomas).
>
> v5 -> v6:
>   1) Remove stray code which didn't get used, say lsdc_of_get_reserved_ram
>   2) Fix all typos I could found, make sentences and code more readable
>   3) Untangle lsdc_hdmi*_connector_detect() function according to the pipe
>   4) After a serious consideration, we rename this driver as loongson.
>      Because we also have drivers toward the LoongGPU IP in LS7A2000 and
>      LS2K2000. Besides, there are also drivers about the external encoder,
>      HDMI audio driver and vbios support etc. This patch only provide DC
>      driver part, my teammate Li Yi believe that loongson will be more
>      suitable for loongson graphics than lsdc in the long run.
>
>      loongson.ko = LSDC + LoongGPU + encoders driver + vbios/DT ...
>
> v6 -> v7:
>   1) Add prime support, self-sharing is works. sharing buffer with etnaviv
>      is also tested, and its works with limitation.
>   2) Implement buffer objects tracking with list_head.
>   3) S3(sleep to RAM) is tested on ls3a5000+ls7a2000 evb and it works.
>   4) Rewrite lsdc_bo_move, since ttm core stop allocating resources
>      during BO creation. Patch V1 ~ V6 of this series no longer works
>      on latest kernel. Thus, we send V7 to revival them.
>
> v7 -> v8:
>   1) Zero a compile warnnings on 32-bit platform, compile with W=1
>   2) Revise lsdc_bo_gpu_offset() and minor cleanup
>   3) Pageflip tested on the virtual terminal with following commands
>
>      modetest -M loongson -s 32:1920x1080 -v
>      modetest -M loongson -s 34:1920x1080 -v -F tiles
>
>     It works like a charm, when running pageflip test with dual screnn
>     configuration, another two additional bo created by the modetest
>     emerged, VRAM usage up to 40+MB, well we have at least 64MB, still
>     enough.
>
>     # cat bos
>
>         bo[0000]: size:     8112kB VRAM
>         bo[0001]: size:       16kB VRAM
>         bo[0002]: size:       16kB VRAM
>         bo[0003]: size:    16208kB VRAM
>         bo[0004]: size:     8112kB VRAM
>         bo[0005]: size:     8112kB VRAM
>
> v8 -> v9:
>   1) Select I2C and I2C_ALGOBIT in Kconfig and should depend on MMU.
>   2) Using pci_get_domain_bus_and_slot to get the GPU device.
>   3) Other minor improvements.
>
>   Those patches are tested on ls3a5000 + ls7a1000 CRB, ls3a5000 + ls7a2000
>   evb, and lemote a1901 board(ls3a4000 + ls7a1000). On loongson mips CPU,
>   the write combine support should be enabled, to get a decent performance
>   for writing framebuffer data to the VRAM.
>
> v9 -> v10:
>   1) Revise lsdc_drm_freeze() to implement S3 completely and correctly.
>      I suddenly realized that pinned buffer can not move and VRAM lost
>      power when sleep to RAM. Thus, the data in the buffer who is pinned
>      in VRAM will get lost when resume. Yet it's not big problem because
>      we are software rendering solution which relay on the CPU update the
>      front framebuffer. We can see the garbage data when resume from S3,
>      but the screen will show correct image as I move the cursor. This is
>      due to the cpu repaint. v10 of this patch make S3 perfect by unpin
>      all of BOs in VRAM, evict them all to system RAM.
>
> v10 -> v11:
>   1) On double screen case, the single giant framebuffer is referenced by
>      two GEM object, hence, it will be pinned by prepare_fb() at lease two
>      times. This cause its pin count > 1. V10 of this patch only unpin VRAM
>      BOs once when suspend, which is not correct on double screen case. V11
>      of this patch unpin BOs until its pin count reach to zero when suspend.
>      Then, we make the S3 support complete finally. With v11, I can't see
>      any garbage data after resume. Tested on both ls7a1000 and ls7a2000
>      platform, with single screen and double screen configuration.
>   2) Fix vblank wait timeout when disable CRTC.
>   3) Test against IGT, at least fbdev test and kms_flip test passed.
>   4) Rewrite pixel PLL update function, magic numbers eliminated (Emil)
>   5) Drop a few common hardware features description in lsdc_desc (Emil)
>   6) Drop lsdc_mode_config_mode_valid(), instead add restrictions in dumb
>      create function. (Emil)
>   7) Untangle the ls7a1000 case and ls7a2000 case completely (Thomas)
>
> v11 -> v12:
>   none
>
> v12 -> v13:
>   1) Add benchmark to figure out the bandwidth of the hardware platform.
>      Usage:
>      # cd /sys/kernel/debug/dri/0/
>      # cat benchmark
>
>   2) VRAM is filled with garbage data if uninitialized, add a buffer
>      clearing procedure, clear it on the BO creation time.
>   3) Update copyrights and adjust coding style (Huacai)
>
> v13 -> v14:
>   1) Trying to add async update support for cursor plane.
>
> Sui Jingfeng (2):
>    drm: add kms driver for loongson display controller
>    MAINTAINERS: add maintainers for DRM LOONGSON driver
>
>   MAINTAINERS                                   |    8 +
>   drivers/gpu/drm/Kconfig                       |    2 +
>   drivers/gpu/drm/Makefile                      |    1 +
>   drivers/gpu/drm/loongson/Kconfig              |   17 +
>   drivers/gpu/drm/loongson/Makefile             |   20 +
>   drivers/gpu/drm/loongson/lsdc_benchmark.c     |  133 ++
>   drivers/gpu/drm/loongson/lsdc_benchmark.h     |   13 +
>   drivers/gpu/drm/loongson/lsdc_crtc.c          | 1066 +++++++++++++++++
>   drivers/gpu/drm/loongson/lsdc_debugfs.c       |   91 ++
>   drivers/gpu/drm/loongson/lsdc_device.c        |  104 ++
>   drivers/gpu/drm/loongson/lsdc_drv.c           |  495 ++++++++
>   drivers/gpu/drm/loongson/lsdc_drv.h           |  451 +++++++
>   drivers/gpu/drm/loongson/lsdc_gem.c           |  324 +++++
>   drivers/gpu/drm/loongson/lsdc_gem.h           |   37 +
>   drivers/gpu/drm/loongson/lsdc_gfxpll.c        |  199 +++
>   drivers/gpu/drm/loongson/lsdc_gfxpll.h        |   52 +
>   drivers/gpu/drm/loongson/lsdc_i2c.c           |  179 +++
>   drivers/gpu/drm/loongson/lsdc_i2c.h           |   29 +
>   drivers/gpu/drm/loongson/lsdc_irq.c           |   71 ++
>   drivers/gpu/drm/loongson/lsdc_irq.h           |   16 +
>   drivers/gpu/drm/loongson/lsdc_output.h        |   21 +
>   drivers/gpu/drm/loongson/lsdc_output_7a1000.c |  161 +++
>   drivers/gpu/drm/loongson/lsdc_output_7a2000.c |  531 ++++++++
>   drivers/gpu/drm/loongson/lsdc_pixpll.c        |  481 ++++++++
>   drivers/gpu/drm/loongson/lsdc_pixpll.h        |   86 ++
>   drivers/gpu/drm/loongson/lsdc_plane.c         |  781 ++++++++++++
>   drivers/gpu/drm/loongson/lsdc_probe.c         |   56 +
>   drivers/gpu/drm/loongson/lsdc_probe.h         |   12 +
>   drivers/gpu/drm/loongson/lsdc_regs.h          |  402 +++++++
>   drivers/gpu/drm/loongson/lsdc_ttm.c           |  610 ++++++++++
>   drivers/gpu/drm/loongson/lsdc_ttm.h           |   99 ++
>   31 files changed, 6548 insertions(+)
>   create mode 100644 drivers/gpu/drm/loongson/Kconfig
>   create mode 100644 drivers/gpu/drm/loongson/Makefile
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_benchmark.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_benchmark.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_crtc.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_debugfs.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_device.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_drv.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_drv.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_gem.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_gem.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_gfxpll.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_gfxpll.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_i2c.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_i2c.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_irq.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_irq.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_output.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_output_7a1000.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_output_7a2000.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_pixpll.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_pixpll.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_plane.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_probe.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_probe.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_regs.h
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_ttm.c
>   create mode 100644 drivers/gpu/drm/loongson/lsdc_ttm.h
--
Jingfeng